Doping dependence of the ultrafast electronic dynamics ofY1−xPrxBa2Cu3

Abstract

Time-domain spectroscopy, which probes the dynamics of the electronic states near Fermi surface that are associated with superconductivity, has proven to be a powerful method for providing insights into the fundamental nature of both pseudogap and superconducting gap. This study shows that the unique T-x phase diagram with the time-evolving ultrafast dynamics of Y 1−x Pr x Ba 2 Cu 3 O 7−␦ can be used to identify clearly the Nernst, pseudogap, and superconducting regions. All of the orders appear together at a specific delay time, such as 1.2-3 ps, after pumping by an ultrashort pulse. These discoveries suggest that the Nernst effect, the pseudogap and even superconductivity may have the same physical origin.

Amplitude dynamics of the charge density wave in LaTe3 : Theoretical description of pump-probe experiments

“…The CDW state is characterized by both the modulation of the electronic density δρ e (r) = A exp(iQ · r) + c.c., (1) and the displacements of ions…”

“…Dynamics of phase transitions associated with spontaneous symmetry breaking remains an interesting subject both theoretically and experimentally. Thanks to the advances in time-resolved pump-probe techniques, it is now possible [1][2][3][4][5][6][7][8][9] to perturb an ordered state and then monitor its fast non-adiabatic recovery. For strong perturbations, one can observe a passage through an ordering transition, register the emergence of ordered phases, and measure time evolution of diverse system parameters with a subpicosecond resolution.…”

Ultrafast pump-probe spectroscopic signatures of superconducting and pseudogap phases in YBa2Cu3O7−δ films

“…[31][32] However, for OD YBCO samples, which is the subject of this study, the PG feature was either unobserved 9,19,25,26 or, in a very few cases, 11,30 reported as a weak transient clue of the pseudogap. To explain those earlier results, we note that, apart from the quality of the samples, the relatively weak laser excitation could be another important factor.…”

“…For example, in the previous measurements on optimally-doped (OD) YBa 2 Cu 3 O 7-δ (YBCO) samples, the observed sign of time-resolved differential reflectivity (ΔR/R) was reported to be either positive or negative. 9,11,25,26 This fundamental discrepancy was attributed to the dependence of ΔR/R on several factors including laser power, 15,23 wavelength, 25,27 polarization, 25,28 and repetition rate 24,29 . Furthermore, in a recent effort to uncover the transient optical signatures of the pseudogap (PG) phase, [11][12][13][14]28,[30][31][32] and elucidate a possible relationship between the PG state and SC state in OD YBCO [31][32] , the PG phase was either identified as a weak transient feature 11,30 or found to be completely absent from the spectra.…”

“…Furthermore, in a recent effort to uncover the transient optical signatures of the pseudogap (PG) phase, [11][12][13][14]28,[30][31][32] and elucidate a possible relationship between the PG state and SC state in OD YBCO [31][32] , the PG phase was either identified as a weak transient feature 11,30 or found to be completely absent from the spectra. 9,19,25,26 Here, we report on a new procedure to obtain the definitive ultrafast optical RT model. 22 The OD YBCO thin film sample with a thickness of 48 unit cells is grown on an atomically flat single crystal SrTiO 3 (001) substrate in the layer-by-layer fashion by laser MBE.…”